성년의 남성은 노화가 진행됨에 따라 혈중 testosterone이 감소 되면서 갱년기증상을 나타낸다. 랫드(Ratus norvegicus)는 생식 시스템이 인간과 매우 유사하여 실험 모델로 그 활용 빈도가 높은 동물이다. 본 연구에서는 남성갱년기 동물모델 확립을 위해 22주령과 50주령 랫드의 생식 기관 무게, testosterone 을 포함하는 호르몬 및 생화학적 변화에 대한 비교 연구를 진행하였다. 그 결과 22주령에 비해 50주령의 체중 및 생식기관 무게가 높게 측정 되었다. 혈중 dihydrotestosterone(DHT)는 50주령에 비해 22주령에 서 높게 측정되었다. Aspartate aminotransferasel(AST), alanine aminotransferase(ALP), total protein (TP), triglyceride(TG)와 total cholesterol(TC)은 50주령 랫드 그룹에서 유의적으로 증가되었다. 또한, 혈중 luteinizing hormone(LH)는 50주령 랫드 그룹에서 현저히 감소되었으나, follicle stimulating hormone(FSH)는 두 그룹간 차이를 나타내지 않았다. 본 연구의 결과들을 종합할 때 22주령과 50주령 랫드의 비교 실험은 남성갱년기 동물모델 시스템으로 적용 가능할 것으로 판단되며 보다 확고한 남성갱년기 전용 동물모델 시스템 확립을 위해서는 생육기간에 따른 다양한 인자들에 대한 지속적인 연구가 진행되어야 할 것으로 판단된다.

Oral exposure of humans by excess amounts of arsenic may cause disturbances of the reproductive system. In the present study, such exposure was modelled in rats, with the support of sperm principal parameters and histopa-thological observations. Male Sprague–Dawley rats were randomly divided into three groups where the group I was served as a normal control, group II was received sodium meta-arsenite as arsenic (10 mg/kg b.w/day) and a combi-nation of sodium meta- arsenite and sodium selenite (3 mg/kg b.w/day) in group III. After 6 weeks, there was no significant change in testis weight and in total motility of all the three experimental groups, whereas, rapid moving spermatozoa, moderately moving spermatozoa and slow moving spermatozoa were significantly decreased in arsenic treated rats as compared to control rats. The other sperm principal parameters like progressiveness, average path velocity, straightness linear velocity (VSL), curvilinear velocity (VCL), straightness, linearity sperm head elongation ratio, area, linearity amplitude of lateral head department (ALH) and beat cross frequency (BCF) were found to be reduced in arsenic intoxicated rats. These results are not correlated with the histological studies. On oral admini-stration of selenium ameliorated the adverse effects of arsenic as compared to arsenic alone treated rats. Our findings clearly demonstrate that administration of selenium could prevent some of the deleterious effects of arsenic in the testis.

Iron catalyzes the production of free radicals, which can be related to a variety of pathological events, such as cancer and aging. The effect of dietary iron was investigated on formation of colonic aberrant crypt foci (ACF) induced by azoxymethane in male F344 rats. Animals were fed three different diets, including iron-deficient (3 ppm Fe), iron-normal (35 ppm Fe), and iron-overloaded (350 ppm Fe) diets for eight weeks. During the first and second weeks of the experiment, animals received two subcutaneous injections of azoxymethane (AOM, 15 mg/kg body weight) to induce ACF. After staining with methylene blue, the total numbers of ACF and aberrant crypts (AC) were counted on the colonic mucosa. Analysis of blood and serum was performed using a blood cell differential counter and an automatic serum analyzer. Iron-deficient diets induced a significant decrease in red blood cell counts and the values of hemoglobin concentration, hematocrit, mean corpuscular hemoglobin, and mean corpuscular volume, while an iron-overloaded diet did not affect these values. The iron-overloaded diet induced an increase in deposits of iron in the liver of rats, as determined by the ICP method and Perl’s staining. The numbers of ACF per colon showed a slight increase in iron-overloaded or iron-deficient rats, without statistical significance, compared to iron-normal rats. The number of total AC per colon in iron-overloaded rats was significantly higher than that in iron-normal rats (p<0.05). The number of large ACF (≥ 4 AC per ACF) in iron-overloaded rats was also significantly higher than that in iron-normal rats (p<0.05). These results suggest that dietary iron intake may play an important role in colon carcinogenesis in humans and animals.

Phytic acid (PA) (Inositol hexaphosphate, IP6) is a naturally occurring polyphosphorylated carbohydrate that is present in substantial amounts in almost all plants and mammalian cells. Recently PA has received much attention for its role in anticancer activity. In the present study, the preventive effects of PA on colon carcinogenesis were investigated. Six-week old Fisher 344 male rats were fed a AIN-93G purified diet and PA (0.5% or 2% PA in water) for 8 weeks. The animals received two (1st and 2nd week) injections of azoxymethane (AOM, 15 mg/kg b.w.) to induce colonic aberrant crypt foci (ACF). After sacrifice, the total numbers of aberrant crypts (AC) and ACF in colonic mucosa were examined after staining with methylene blue. Blood and serum were analyzed with a blood cell differential counter and an automatic serum analyzer. AOM induced the total numbers of 142.3 ± 22.3 ACF/colon and 336.6 ± 55.1 AC/colon. PA at the doses of 0.5 and 2% decreased the numbers of ACF and AC/colon in a dosedependent manner. The numbers of ACF/colon and AC/colon by PA at the dose of 0.5% were 124.4 ± 28.5 and 302.7 ± 67.3, respectively. PA at the dose of 2% significantly decreased the ACF and AC numbers to 109 ± 18.1 and 254.8 ± 50.6, respectively (p < 0.01). Especially, 2% PA significantly reduced the number of large ACF ( ≥ 4 AC/ ACF) from 26.8 ± 6.2 ACF/colon to 15 ± 6.7 ACF/colon (p < 0.01). Although some parameters in blood counts and serum chemistry were changed compared with the control, no specific toxicity was found. These findings suggest that phytic acid can be a chemopreventive agent for colon carcinogenesis resulting from inhibition of the development of ACF in the F344 rat.

생태계는 수은의 화학적 형상 및 산업화에 따른 방출로 지속적이면서 다양하게 오염된다. 또한 수은은 화학적 여러 형태로 분류되며 쉽게 기화되는 성질로 인해 수은을 공정하는 과정에서 수많은 근로자들이 쉽게 급성 혹은 만성 중독이 될 수 있다. 그러나 수은의 유독성이 알려져 있기는 하나 생체가 환경에서 노출 가능한 저농도의 수은 영향에 대해서는 정확한 접근이 이루어지지 않고 있다. 따라서 본 실험은 이온화 방사선과 염화수은(II)의 영향을 비교해보고자 수행하

In recent reports, the multiple reproductive defects such as cryptorchidism, hypospadias, epididymal cysts, low sperm counts, and testicular cancers are increased in humans, and these changes were doubted by the chemicals with estrogenic or antiandrogenic activities in our environment. To compare the effects of neonatal exposure of di (n-butyl) phthalate and flutamide on the development of reproductive organs and to identify the specific mechanisms of these abnormalities related to the male reproducton, Sprague-Dawley neonate male rats were injected subcutaneously during 5-14 days after birth with corn oil (control), flutamide (0.05, 0.1, and 0.5 mg/animal) and DBP (5, 10, and 20 mg/animal). Animals were killed at 31 (immature) and 42 (pubertal) days of age respectively and blood was collected from abdominal aorta for serum testosterone analysis. Testes, epididymides, seminal vesicles, ventral prostate, levator ani plus bulbocavernosus muscle (LABC), cowpers glands and glans penis were weighed. Expression of steroid hormone receptors (AR and ER) was examined in the testes and ventral prostate. At 31 days of age, ventral prostate, seminal vesicles, LABC, and cowpers glands significantly decreased in the flutamide (0.5 mg/animal) and DBP (20 mg/animal), but serum testosterone levels were not changed. Flutamide slightly delayed the testes descent at the high dose (0.5 mg/animal), but DBP did not show any significant effect on the testes descent at all doses. DBP and flutamide decreased the expression of AR protein in the testes but did not affect the expression of ERa and ER protein in the testes. At 42 days of age, ventral prostate, seminal vesicles, and cowpers glands weights were still significantly decreased at the high dose of flutamide (0.5 mg/animal) and DBP (20 mg/animal), but the weights of testes and epididymides were not different. Serum testosterone decreased significantly in DBP treated animals and slightly, not significantly, in flutamide group. While DBP still significantly decreased the expression of AR protein in testis, flutamide recovered from downregulation of AR protein and did not affect the expression of ERa and ER protein in the testes. Based on these results, flutamide and DBP have shown several similar patterns in reproductive abnormalitis, but some marked differences which may be caused by different acting mechanism.

The purpose of this study was to investigate the effects of garlic diet on blood coagulation in cholesterol-fed rats. 36 male rats were divided into six groups and fed experimental diet for three weeks. Two-levels (2% and 4%) of fresh and boiled garlic were supplemented to the stock diet with 2% cholesterol and 0.25% bile salt for the experimental diet. After the rats fed with experimental diets during 3 weeks, the whole blood coagulation time, the content of plasma fibrinogen, the fibrinolytic activity and the prothrombin time were measured. The results are summarized as follows; 1. Garlic diet have no influence on body weight and food consumption in rats. 2. In the case of cholesterol-fed group, the whole blood coagulation time was decreased 24.3% compared with the normal group(A). But garlic diet group(C) was similar to the normal group(A) and groupD-F was increased 4.9-11.5%. 3. The content of plasma fibrinogen of cholesterol-fed group was higher 114.5% than that of normal gropu(A). In the garlic diets(C-F) the contents of plasma fibrinogen were increased 33.1-63.8%. 4. The fibrinolytic activity of cholesterol diet was decreased 16.2% compared with the normal group(A) but was increased 10.9-44.5% compared to the garlic diets(C-F). 5. The prothrombin time of cholesterol-fed group was decreased 8.9% compared with normal group(A) but was increased 8.0-46.3% in garlic diets(C-F). As mentioned above, the garlic diets increased whole blood coagulation time, prothrombin time and fibrinolytic activity and decreased the content of fibrinogen. For that reason it is thought that the garlic diets have a anticoagulation effect regulating the fibrinogen synthesis in liver.

In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in androgen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.

Circadian timing system plays a major role in a wide range of reproductive function. However it is plausible idea that other environmental and/or internal cue might be simultaneously participated in the optimal regulation of reproductive system. In the present study we extended the reverse feeding (RF) time regimen up to 8 weeks, then measured the general and reproductive indices of the animals. The animals of ad libitum feeding group (Control, CON) have free access to food for 4, 6 and 8 weeks, respectively. The day feeding animals (reverse feeding, RF group) have restricted access to food during daytime (09:00-18:00) for 4, 6 and 8 weeks, respectively. When the feeding schedules were over, key indices were measured. After 4 weeks and 8 weeks of feeding, body weights of animals were not significantly different. However, body weights of 6 weeks RF animals were significantly smaller than those of control animals (CON : RF = g : g, p<0.01). The blood glucose levels of 4 weeks RF animals were significantly decreased compared to the levels of control animals (CON : RF = mg/dL : mg/dL, p<0.01) while the levels of 6 weeks RF and 8 weeks RF animals were not different form those of control animals. Reproductive and non-reproductive tissue weights from 6 weeks RF group were significantly lowered than those from CON group (testis, CON : RF = g : g, p<0.001; epididymis, CON : RF = g : g, p<0.001; seminal vesicle, CON : RF = g : g, p<0.001; prostate, CON : RF = g : g, p<0.01). After 4 weeks and 8 weeks of reverse feeding, sperm counts in RF animals were markedly reduced than those in control animals[CON 4W : RF 4W = : , p<0.001; CON 8W : RF 8W= : , p<0.001]. Present study indicates that RF may induce an adaptable metabolic stress and cause impairment of androgen-dependent reproductive tissues. On-going longitudinal studies will allow a better understanding of the how does mealtime shift affect the reproductive function and exact nature of adaptation.

Circadian rhythmicity (e.g. secretory pattern of hormones) plays an important role in the control of reproductive function. We hypothesized that the alteration of feeding pattern via meal time shift/restriction might disrupt circadian rhythms in energy balance, and induce changes in reproductive activities. To test this hypothesis, we employed simple animal model that not allowing feeding but daytime only feeding. The animals of feeding group (Control) have free access to food for 4 weeks. The day feeding (=reverse feeding, RF) animals (RF group) have restricted access to food during daytime (0900-1800) for 4 weeks. After completing the feeding schedules, body weights, testis and epididymis weights of animals from both group were not significantly different. However, the weights of seminal vesicle (control : RF group = : , <0.01) and prostate (control : RF group = : , <0.001) were significantly lower in RF group animals. The mRNA levels of pituitary common alpha subunit (; control : RF group = AU : AU, <0.001) and (control : RF group = AU : AU, <0.05) were significantly decreased in RF group. The mRNA levels of ACTH were not significantly different. We were unable to find any prominent difference in the microstructures of epididymis, and there were slight alterations in those of seminal vesicles after 4 weeks of reversed feeding when compared to control samples. The present study demonstrates that the shift and/or restriction of feeding time could alter the pituitary gonadotropin expression and the weights of seminal vesicle and prostate in rats. These data suggest the lowered gonadotropin inputs may decrease androgen secretion form testis, and consequently results in poor response of androgen-dependent tissues such as seminal vesicle and prostate.

It is well known that adipose tissue or body fat has been proved as a crucial component of brain-peripheral axis which can modulate the activities of reproductive hormonal axis in female mammals including rodents and human. Concerning the male reproduction, however, the role of adipose tissue has not been thoroughly studied. The present study was carried out to elucidate the effect of a high-fat (HF) diet on the reproductive system of postpubertal male rats. The HF diet (45% energy from fat, HF group) was applied to male rats from week 8 after birth for 4 weeks. The blood glucose levels, body and tissue weights were measured. Histological studies were performed to assess the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus and pituitary, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights (p<0.01) and blood glucose levels (p<0.01) of HF group were significantly higher than those of control animals. Similarly, the weights of epididymis (p<0.05), prostate (p<0.01), seminal vesicle (p<0.01) in HF group were higher than control levels. The weights of testis were not changed. The weights of kidney (p<0.001) and spleen (p<0.01) were significantly higher than control levels while the adrenal and pancreas weights were not changed. There were only slight alterations in the microstructures of accessory sex organs; the shape of luminal epithelial cells in epididymis from HF group were relatively thicker and bigger than those from control animals. In the semi-quantitative RT-PCR studies, the mRNA levels of hypothalamic GnRH (p<0.05) in HF group were significantly higher than those from the control animals. The mRNA levels of kisspeptin in HF group tend to be higher than control levels, the difference was not significant. Unlike the hypothalamic GnRH expression, the mRNA levels of pituitary and were significantly decreased in HF group (p<0.05). The present study indicated that the 4-weeks feeding HF diet during the postpubertal period can alter the hypothalamus-pituitary (H-P) neuroendocrine reproductive system These results suggest that the increased body fat and the altered leptin input might disturb the H-P reproductive hormonal activities in male rats, and the changed activities seem to be responsible for the changes of tissue weights in accessory sex organs.

6-hydroxydopamine(6-OHDA)는 파킨슨 질환 동물 모델의 제조에 널리 사용되는 신경독소로 도파민성 뉴런에 대한 특이적인 독성을 나타낸다. 도파민 신호는 중추신경계의 광범위한 영역에서 생리 기능을 조절하는데, 이에 따라 파킨슨병 환자와 6-OHDA를 처리한 동물들의 신경내분비 활성에 극심한 변화가 있을 것으로 예상할 수 있다. 하지만 6-OHDA 주사 모델에서 시상하부-뇌하수체 신경내분비 회로에 관한 연구들은 전무한 실정이다. 본 연구는

Ethane 1,2-dimethane sulfonate(EDS)은 Leydig cells(LC)만을 선별적 사멸을 유도하는 약물로서 가역적인 테스토스테론(testosterone, T) 결핍 흰쥐 모델을 만드는데 널리 사용된다. 본 연구에서는 수컷 흰쥐 뇌하수체의 생식소자극호르몬인 LH와 FSH의 발현에 미치는 EDS 투여 효과를 조사하였다. 성숙한 수컷 흰쥐(SD strain, B.W.)에 EDS(75 mg/kg, i.p.)를 1회 복강주사하고 주사 후